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Re: find the maxima in a function

• To: mathgroup at smc.vnet.net
• Subject: [mg97088] Re: find the maxima in a function
• From: "Sjoerd C. de Vries" <sjoerd.c.devries at gmail.com>
• Date: Thu, 5 Mar 2009 04:53:11 -0500 (EST)
• References: <golqus$qai$1@smc.vnet.net>

Your function definition has x as an argument, but apart from x it
also depends on y, z and t. With respect to which variable do you want
the function to be maximized?

If it is t, then you could try something like

Solve[D[1/(8*(Pi*t)^(3/2))*Exp[(-(x^2 + y^2 + z^2)/4*t)], t] == 0,
t],

and you should make a plot or so to check whether this is a local/
global minimum or maximum.

You might check FindMaximum and Maximize in the manual.

Cheers -- Sjoerd

On Mar 4, 2:07 pm, Oliver <sch_oliver2... at yahoo.de> wrote:
> Hallo,
> how can one find the maxima by using mathematica for the following functi=
on:
>
> f[x_] := 1/(8*(Pi*t)^(3/2)) * Exp[(-(x^2 + y^2 + z^2)/4*t)]
>
> i mean, the first derivation equal Zero.
> Thanks in advance..
> Oli.